On Trump's shortlist: Indiana Gov. Mike Pence, New Jersey Gov. Chris Christie and former House Speaker Newt Gingrich, according to people familiar with the candidate's thinking.

Pence quickly exited a speaking event in Indianapolis Thursday morning without taking questions from reporters. His staff had not released details of any other planned appearances Thursday.

Pence is running for re-election, but Indiana law prevents him from seeking two offices at once. He faces a Friday deadline to withdraw from the governor's race.

A Republican familiar with Pence's thinking said the paperwork has been drawn up for him to take that step. However, the documents have not been filed, according to the Republican, who insisted on anonymity because that person was not authorized to publicly discuss Pence's plans.

Trump was making his final decision from California, where he is scheduled to attend a series of fundraisers at a distance from many of his closest advisers. His campaign chair, Paul Manafort, is currently in Cleveland, and none of his children are in the state with him.

All three of the finalists have had extensive conversations with Trump and his family in recent days.

Gingrich told The Associated Press he was expecting to hear from Trump one way or the other sometime after 1 p.m. The former Georgia congressman praised Trump for running a "very fair, open process" and said he looked forward to learning the businessman's decision.

Gingrich later posted on Facebook that he would hold a live chat at 2 p.m. about the "vice presidential picks and the VP selection process."

Trump and his new running mate will make their first appearance as a team Friday in New York. The timing is aimed at energizing Republicans ahead of next week's Republican convention in Cleveland.

Each of Trump's top contenders would add significant political experience to the GOP ticket. Trump, a political novice, has said for weeks that he wanted a running mate who could help him work with Congress.

Beyond their political backgrounds, the finalists bring different strengths to the ticket.

Pence, 57, is a steady, staunch conservative who would help calm nervous Republican wary of Trump's impulsive style. He served six terms in Congress before becoming Indiana governor. He also has deep ties to evangelical Christians and other conservatives, particularly after signing a law last year that critics said would have allowed businesses to deny service to gay people for religious reasons.

Trump took notice of Pence during the Indiana primary, noting that the governor had high praise for him despite endorsing one of his rivals.

Gingrich is a boisterous rabble-rouser who has spent decades in Washington and helped define the political battles of the 1990s. The 73-year-old would be the oldest candidate ever to become vice president.

Gingrich has been a steadfast Trump defender for months and has become a trusted adviser to the businessman.

So, too, has Christie. The New Jersey governor quickly endorsed Trump after ending his own presidential bid, stunning many of his supporters.

A former U.S. attorney, Christie, 53, is widely seen as one of his party's most talented retail politicians and has proven himself a biting attack dog on the trail. He's also become a valuable partner for Trump, joining him at events on the trail and taking on the important role of heading Trump's transition planning.

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